In the context of mitigating the impending global warming due to anthropogenic emissions of carbon dioxide, which of the following can be the potential sites for carbon sequestration ? 1. Abandoned and uneconomic coal seams 2. Depleted oil and gas reservoirs 3. Subterranean deep saline formations Select the correct answer using the code given below :
- (a) 1 and 2 only
- (b) 3 only
- (c) 1 and 3 only
- (d) 1, 2 and 3 ✓ UPSC's answer
Why the answer is (d)
• Geological carbon sequestration injects captured CO2 into deep formations that can trap it for millennia.
• Depleted oil and gas reservoirs (2) have proven cap rocks and infrastructure; CO2 injection also enhances oil recovery.
• Deep saline aquifers (3) offer the largest storage capacity worldwide.
• Unmineable coal seams (1) adsorb CO2 onto coal surfaces while releasing methane (enhanced coal-bed methane recovery).
• All three are recognised potential sites.
• Hence 1, 2 and 3, option (d).
Why the other options are wrong
- (a) 1 and 2 only
- Saline formations are also major storage sites.
- (b) 3 only
- Coal seams and depleted reservoirs are also potential sites.
- (c) 1 and 3 only
- Depleted oil and gas reservoirs are also potential sites.
Asked in the GS Paper I of the UPSC Civil Services Preliminary Examination 2017, held on 18 June 2017. Question and answer key: Union Public Service Commission. Explanation: UPSC Answer Check.